The Swede triumphed in the women's 200 metres freestyle, dominating in 1min 57.62secs at Guangdong Olympic Sports Centre.

All her opponents had already raced that morning, with China's Li Bingjie and Wang Jianjiahe and Hungary's Katinka Hosszu showing their fatigue. 

Li finished in 1:59.40, with Wang clocking 2:00.93 and Hosszu 2:02.56.

Sjöström took her second gold in the 100m butterfly, finishing in 57.16, half a second behind her world record of 56.69. 

Kelsi Dahlia of the United States overtook Ranomi Kromowidjojo to finish second in 58.77, the Dutch swimmer third in 58.77.

Hosszu finished fourth in the 200m freestyle having been victorious in the 400m freestyle earlier in the day. 

The three-time Olympic champion and seven-time world champion narrowly beat Li in a time of 4:05.16, her Chinese rival second in 4:05.21.

Li's compatriots were third and fourth, with Zhang Yuhan finishing in 4:07.39 and Wang in 4:07.57. 

Hosszu is one of three leading swimmers suing FINA over allegedly violating US antitrust laws, following the governing body’s opposition to an International Swimming League event in Turin in December.

FINA and ISL are locked in dispute, with FINA allegedly barring athletes from taking part in ISL events. 

Many see the new Champions Swim Series as a direct response from FINA to criticism from athletes.

The competition concludes tomorrow with 14 more races.